Double booknig cross post

[ictcrystal]

Hey can someone help me out with this question



http://www.access-programmers.co.uk/...d.php?t=276168

i dont know if i should just rewrite it or send the link because seem to be posting the link on my posts??

[Rawb]

I'm afraid I don't understand the question.

[ictcrystal]

Hello
My question is really what is the querytelling me in terms of a double bookings?
I just dont understand the time field.. i know that the query removes a time for a dentist when somebody tries to book a time already used. but i fail to understand it in this query

[Rawb]

It doesn't remove anything. I can't see the whole Query, but this looks like a simple SELECT Query. It can only show information, not change, add, or delete information.

From what little I can see, the Query does nothing more than show all bookings for a specific user (dentist) on a given day. That means unless there's more criteria in the Query that you aren't showing, it's up to you to determine if there are double-bookings and remove/reschedule them as necessary.

[ictcrystal]

the thing idont understand is.. why has it got the whole [forms]. stuff? why not just select the field i dont understand the criterias (forget the double booking situation)

[Rawb]

Ah,

Those lines beginning with [Forms]! are pointing to specific Controls on a Form that you can fill out to specify the dentist and date in question. Without those two Criteria, the Query would return the entire list of all appointments, for all dates (and all dentists), including ones that have already happened or that are for dentists no longer working there.

As for why the programmer decided to reference the Form Controls directly in the Query instead of just passing the information as a Filter or WhereCondition, I couldn't tell you. There are times when you actually have to it this way, but they are few and far between. Personally, I try never to use this method as it limits how you can use the Query and, if you have to rename/move anything, it can break stuff in a manner that's hard to troubleshoot.